During the production of heavy oil, oil with high viscosity and high specific gravity, it is sometimes desirable to inject a recovery enhancement fluid into the reservoir to improve oil mobility. One type of recovery enhancement fluid is steam that may be injected using a cyclic steam injection process, which is commonly referred to as a “huff and puff” operation. In such a cyclic steam stimulation operation, a well is put through cycles of steam injection, soak and oil production. In the first stage, high temperature steam is injected into the reservoir. In the second stage, the well may be shut to allow for heat distribution in the reservoir to thin the oil. During the third stage, the thinned oil is produced into the well and may be pumped to the surface. This process may be repeated as required during the productive lifespan of the well.
It has been found that it may be desirable to periodically perform casing integrity testing on wells that utilize cyclic steam stimulation. In fact, some jurisdictions require casing integrity testing for such wells at predetermined intervals or frequencies. Typically, to perform the casing integrity testing, a workover rig is used to remove the production tubing and pumping equipment installed in the well and to run the testing string into the well. Thereafter, a fluid may be pumped into the well and pressurized to test the casing integrity. If the casing passes the test, the testing string may be removed and the production tubing and pumping equipment may be reinstalled. While casing integrity testing of wells performing cyclic steam stimulation operations is desirable, there are costs associated with the testing both from a financially standpoint as well as in terms of lost or delayed production.
Accordingly, a need has arisen for an improved tool system for cyclic steam injection. A need has also arisen for such an improved tool system that does not require a workover rig to performing casing integrity testing. Further, a need has arisen for such an improved tool system that does not require removal of the tool system prior to performing casing integrity testing.